Power supply system



April 16, 1935. J. KAAR POWER SUPPLY SYSTEM 4 Original Filed June 18, 193 2 I [Sauna of l'kciromoidvelme Fig.3.

Fig.2.

Inventor: Ira Kaar, y

His' Attoi'fne y.

Patented Apr. 16, 1935 g I I I v I 1,998,321

UNITED STATES oFF-ircs TY 155,998,321 7 I I I eral Electric Company, a, corporation of New York Application June'18, 1932-, Serial No. 618,008

Renewed October 19, 1934 '1 Claims. 01. 250-17) My invention relates to power supply systems grid biasing-potential indicated at 8: and with a and particularly to such supply systems for use source of anode supply potentialindicatedby the in connection with electron discharge devices. rectangle at 9. This source of anodesupply po- In radio telegraphy, for example, where the tential may, for example, comprise thearmature supply of high frequency oscillations to the grid of a dynamo-electric machine. The armature 5 of one or more electron discharge devices is conpossesses a certain amountof internalresistance trolled in accordance with desired signals, the whichis indicated in the drawing atlo-yandinanode impedance ofthe discharge device is vaternal inductance which is indicated at II. The ried overa wide range with the telegraphic inelectromotive force generated in the armature 1 0 terruption in the transmitted signals, that is, maybe considered as being inducedbetween the 10 when oscillations are present upon the grid the terminals I2 connected'in series'with the 'resist anode impedance of the device is relatively low ance I0 and inductance II. Frequently a1 conwhereas when the oscillations are interrupted the denser indicated at I3 is connection in shunt with anode impedance is high. The anode voltage for the armature of the dynamorelectric machirielfor these discharge devices is commonly supplied current'smoothing-and other purposes? rnave 15 from a dynamo-electric machine, orother type of shown a, resistance I4 connected in series with power source having a certain amount of resistthe condenser I3 the purpose of which will be ance and inductance. Also commonly a conexplained hereinafter. I denser 1 is connected across the terminals of the Considering the typeof system hereinbeforede- 2 power source for current smoothing purposes; as scribed bnt in which the resistance ldeis omitted,

to smooth out commutator ripple,etc. the operation may be indicatedby the charactera It has; been found that with this type ofpower istic shown in Fig. 2. This characteristic. indisource the character of the transmitted impulses catesthe variationini'ntensity of oscillationssupis affected by transient conditionsin the power plied to the antenna with respect to'time during supply. It is accordingly one of the objects of my the interval of a. telegraphicdot or dash. Thus in 25 invention to provide a power source which is free this figure the intensity of the high frequency from these transient effects. oscillations is plotted as ordinates and timeaas l rfurtherobject of my invention is to provide abscissas. Thus, for example, if I assume that a power source which, while it has a certain the key 1 is closed at a time corresponding tothe 3o amoimtof inherent inductance, or capacity, operextreme left hand portion or the curve representates with respect to the load circuitas though its ed in this figure, it willbeseen that in this porinternal impedance were pure resistance andin tion of the curve the-intensity of' the high frethe nature of a dry cell, or storage battery. quency oscillations supplied to the antenna is My invention will be better understood from large and is comparable withthat which is supthe following description when considered in conplied late in the telegraphic interval, but thatthe 35 nection with the accompanying drawing and its intensity first rapidly diminishes and then in-. scope willbe pointed out in the appended claims. creases to a fairly steady value later in the tele Referring to the drawing, Fig. 1 represents an graphic interval. This form of the curve is due embodiment of my invention; and Figs. 2 and'3 tothe factthat atthe time the key 'Iis first closed 40 indicate certaincharacteristic's with reference to the condenser I3v is'fully charged and potentialis 40 its operation. supplied to the anode of the discharge device 'In Fig. l of the drawing, I have shown therein equal to the normal no-loadvoltage of the source for purposes ofaillustration, a radio telegraph 9. However, after thekey I is closed, the imtransmitter of a conventional type, this transpedanceof the discharge device I is immediately mitter comprising an electron discharge amreduced with the result that the condenser 3 dis- 45 plifier I, having a tunedgrid circuit 2 and a charges through the low impedance of the distuned anode circuit 3, the latter of which is c'oucharge device for an interval at the left handporv pled to asuitable radiating system 4. A source tionof thelcurve of Fig. 2 while current is buildof' high frequency oscillations 5 is coupled by ing up through the. inductance of the source/9.

I meansof transformer fi to the input circuit of the Thus, for example, if it wereassumed that the 50 amplifier I. The supply of oscillations from this source 9 was disconnected from the condenser I3: source is arranged to be. interrupted in accordsimultaneously with the closingof the switch 1, ance with telegraphic signals by means of key the condenser I3 would continue to. discharge 1, or its equivalent. along the logarithmic curve indicated by the dot- The amplifier l is provided with a source of ted line I5 in Fig. 2. However, as the current 55 builds up in the source 9 the condenser again becomes charged to a voltage corresponding to the full load voltage of the source S and in a time depending upon the rate of current increment through the inductance H. The rate of increment is shown by line IS. The voltage on the discharge device i is then increased in accordance with the heavy line curve of the figure.

To avoid this undesirable character of the transmitted impulse, in accordance with my invention the aforementioned resistance [4 is connected in circuit with the condenser i3, this resistance having a value equal to the internal resistance [0 of the source 9 and equal to the square root of the ratio of the inductance i l of the source 9 to the capacitance of the condenser l3. With these constants so adjusted it has been found that the impulses supplied to the antenna 4 are then of the character shown in Fig. 3, the transient condition which appears at the left hand portion of Fig. 2 being entirely eliminated.

It is well known in the theory of parallel resonance that when the resistance of the inductive branch of a parallel circuit is equal to the resistance of the capacitive branch of this parallel circuit, and each of these resistances is equal to the square root of the ratio of the inductance of the inductive branch to the capacitance of the capacitive branch, then the circuit becomes aperiodic, the reactance of the circuit is zero for all frequencies, and the resistance is constant for all frequencies. This phenomenon is explained in the Principles of Radio Communication by J. H. Morecroft, second edition, page 93.

Thus the effect of resistance 14 adjusted to the value above specified is to render the network I 0, II, l3, M of zero effective reactance at all frequencies. Accordingly an electromotive force may be induced in this circuit at any point and varied as desired Without setting up transient effects due to reactance, either capacitive or inductive. Further, any variation of current through the system, or due to variation in load, for example, is not accompanied by transient effects due to reactance in the system. Since the system is one which presents pure resistance to the anode circuit of the discharge device it acts in the same way as a dry cell or storage battery.

It will be apparent that my invention is not limited to use in connection with dynamo electric machine or to systems in which the electromotive force is induced in the inductive branch of the system but that it is applicable independently of the point in the system at which the electromotive force is produced.

While I have shown but a single application of my invention, it will be understood that I do not wish to be limited thereto since its utility may extend to any system in which it is desired that variations in load or in the applied electromotive force, may take place without transients being produced due to the inherent reactance of the system. I therefore contemplate by the appended claims to cover any modifications of the system which fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. In combination, a source of electromotive force having internal resistance and reactance, and a shunt to said source having resistance substantially equal to said first resistance and reactance of opposite sign to that of said first reactance, the square root of the ratio between said reactances being substantially equal to either of said equal resistances.

2. In combination, a network including a source of electromotive force having internal resistance and reactance, a variable load connected across said source, said network further including a shunt across said source having resistance and reactance, said last resistance and reactance having such values with respect to said first resistance and reactance that said network comprising said source and said shunt is aperiodic.

3. In combination, a source of voltage having internal resistance and reactance, and a shunt to said source having reactance of opposite sign to that of the reactance of said source and resistance substantially equal to the resistance of said source and to the square root of the ratio of said reactances.

4. In combination, a network including a source of electromotive force having internal reactance and resistance, said network fiu'ther including a shunt to said source having resistance and having reactance of opposite sign to said first-named reactance and resistance, said last-named reactance and resistance having such values relative to the values of said first-named reactance and resistance that the reactance of said network is substantially zero for all frequencies.

5. In combination, a network including a dynamo-electric machine and a condenser connected in shunt to said machine and a resistance in series with said condenser, said resistance having such value that said network comprising said dynamo-electric machine and said condenser and resistance is aperiodic.

6. The combination, in a high frequency transmitter, of an electron discharge device having an anode, a cathode and a grid, an output circuit connected to said anode, means to supply high frequency impulses to said grid in accordance with desired signals whereby said signals are repeated to said load circuit, a source of anode voltage having reactance and resistance, said reactance being sufficient to retard substantially the rise to normal value of each of said impulses as repeated to said load circuit, and means to eliminate the effect of said reactance upon said impulses whereby said impulses are faithfully repeated to said load circuit, said means comprising a capacitance and resistance in shunt to said source.

'7. The combination, in a high frequency transmitter, of an electron discharge device having an anode, a cathode and a grid, an output circuit connected to said anode, means to supply high frequency impulses to said grid in accordance with desired signals whereby said signals are repeated to said load circuit, a source of anode voltage comprising a dynamo-electric machine connected between said anode and cathode and a condenser connected in shunt to said dynamo electric machine, the reactances of said machine and of said condenser being sufficient to cause the value of each of said impulses first to be relatively large, then to diminish rapidly to a value substantially less than normal and finally to increase gradually to normal, and means to eliminate the effect of said reactances upon said impulses whereby said impulses are faithfully repeated to said load circuit, said means comprising a resistance in series with said condenser.

IRA J. KAAR. 

